Meta-analysis plays a key role in setting policy and in planning new research. In the field of substance abuse prevention, meta-analyses have been used to determine the relative impact of competing treatments for addiction, to estimate prevalence of addiction-related diseases, to plan targeted interventions, to assess the cost-effectiveness of competing treatments, and to assist in planning more effective research. A systematic review and meta-analysis requires a substantial investment of time and resources. The time required is typically a year or more, and the cost can exceed a million dollars. Therefore, before embarking on a systematic review the researcher should conduct a power analysis to ensure that the review will have appropriate statistical power to yield a meaningful result. At present however, while the formulas for this kind of power analysis have been published, no mechanism exists for actually applying these formulas. The goal of this project is to develop software to compute power for meta-analysis. The program would be used to plan a new systematic review, to understand the implications of a completed review, to make decisions about updating a review with the inclusion of new studies, and to plan a set of primary studies that would be synthesized by meta-analysis. It will incorporate a sophisticated user interface to address the kinds of real-world issues that must be addressed in a power analysis. Meta-analysis plays a key role in setting policy and in planning new research. In the field of substance abuse prevention, for example, meta-analyses have been used to determine the relative impact of competing treatments for addiction. The goal of this project is to develop software to compute power for meta-analysis. The program would be used to plan a new systematic review and to understand the implications of a completed review. [unreadable] [unreadable] [unreadable] [unreadable]